1. Field of the Invention
The present invention relates to a display apparatus and, in particular, relates to a projective display apparatus, such as a liquid crystal projector apparatus and a DLP (Digital Light Processing) projector apparatus, or the liquid crystal display.
2. Description of the Related Art
A display apparatus corresponding to a plurality of signal types, such as a digital RGB signal of a computer, an analog RGB signal, a HDMI (High-Definition Multimedia Interface) signal of an audio-video equipment, a component video signal and a composite video signal, is required. While input terminals different from each other may be provided to these various signals on the display apparatus, there is an example where one input terminal is used for different signal types, for example the analog RGB signal and the component video signal, in order to save space. Even when one input terminal is used for different signal types, the signal type in each input can be selected from an input select menu of OSD (On Screen Display) by an operation of a user. However, since the operation is annoying for the user, a technology to automatically determine the signal type is required.
Japanese patent Laid-Open No. 2007-241261 discloses a technology to determine a type of a synchronizing signal input from an input terminal by detecting the synchronizing signal type and a status of the frequency or the like.
However, in a conventional technology disclosed in Japanese Patent Laid-Open 2007-241261, in a case where the input terminal used for different signal types (or input terminal having a similar function) is additionally installed, a single line of a detector for detecting a status of the synchronizing signal must be additionally installed and the cost also increases. Therefore, the detector for detecting the status of the synchronizing signal is configured to not used in only each terminal but be used in different terminals by a switch, and the switch is synchronized with an input select menu operation of the user. However, the configuration cannot determine the signal type at one input terminal not selected by the user.